+1 for PVC pipe in the walls. A friend of mine did that, and it's worked on great for him. If you have vent system for heating and cooling, it might be worthwh

+1 for PVC pipe in the walls. A friend of mine did that, and it's worked on great for him. If you have vent system for heating and cooling, it might be worthwhile to look at smart systems with per room control. In my house it's all or nothing, so the bathroom can be 85F while the living room is 65F. (My low tech solution was to cut out thin cardboard from cereal boxes and place it under the vent covers. It's visually unobtrusive, easy to do, and makes a big difference in the heating / cooling effectiveness.)